Dibenzylidene sorbitol acetals ("DBS"), substituted DBS, such as can be made with alkyl substituted aromatic aldehydes, and related acetals have found utility as nucleating agents, clarifying agents, gelling agents, processing aids, and strength modifiers in polyolefin resins, polyester resins, deodorant, and antiperspirant compositions; hydrocarbon fuels; waste liquids, especially those containing organic impurities; and paint.
DBS derivative compounds are typically prepared by the condensation reaction of two moles of an aromatic aldehyde with one mole of a polyhydric alcohol, such as xylitol or sorbitol. Examples of suitable processes may be found in Murai et al., U.S. Pat. No. 3,721,682; Murai et al., U.S. Pat. No. 4,429,140; Machell, U.S. Pat. No. 4,562,265; Kobayashi et al., U.S. Pat. No. 4,902,807; and Scrivens et al., U.S. Pat. No. 5,731,474. All of these references are hereby incorporated by reference in their entirety.
DBS is generally provided in powder or pellet form prior to introduction within polyolefin formulations. The DBS will basically melt into the polyolefin upon exposure to sufficient heat and then be mixed throughout the resultant composition. Such a powder or pellet form presents certain problems and limitations upon use of the DBS. For instance, such solid forms are difficult to handle and thus may easily be spilled or lost upon use; powder forms provide potentially hazardous dusting problems; powder forms also tend to present flow difficulties within molding machinery; and pellet forms also require duplicitous extruding costs. Such waste and/or cost of product is undesirable because the cost of DBS is relatively high. Pellet and powder forms also provide difficulty during processing as thorough melting or mixing may not be accomplished. Thus, a liquid form for DBS is both wanted and necessary to lower costs and facilitate mixing with target polyolefin compositions. To date, it is believed that there; are no teachings or fair suggestions of a fluid dispersion of a polyolefin clarifying or nucleating agent. The difficulties associated with processing, such as proper low viscosities and continuous compatibility of the DBS-containing dispersion with the desired polyolefins have heretofore been too problematic, primarily due to the intrinsic thixotropic characteristics of DBS derivatives.